Colored light is used in many applications where scene setting and atmosphere creation is important. Examples of applications exist inter alia in the fields of theatre lighting, architecture lighting (inter alia for city beautification), shops, hotels, restaurants, hospitals, schools, office spaces. Today this is mostly accomplished by combining white light sources with colored filters in order to obtain desired colors.
As an alternative, systems with multi-colored LEDs can be used. Such systems are attractive because they generate the desired colors without filters. This has an efficiency advantage and, more importantly, colors can be changed by the electronics: there is no need to change filters in order to change color; all colors are directly available by combining inter alia a number LEDs of different prime colors. Having electronically regulated colors allows various automatic programming methods to be used to control the lighting system and the fact that filters are omitted results in easier supply chain (no filters needs to be removed) and color consistency (replaced filter might introduce variation). The market for these systems is quickly growing as LED performance improves.
In multi-channel, high flux LED applications such as e.g. CDM replacement spots and multi-color entertainment spots (for theatre/touring/stage/studio applications) a large number of LEDs may be needed and the LEDs should be packed on a small array in a robust way. The performance of an assembly of individual LED packages, such as Rebels, is often limited. On the other hand dedicated large LED arrays, such as fabricated by the company Enfis, LEDEngine have intrinsically a low yield and they are too expensive for many applications. There is thus a need for a scalable solution than can be manufactured and/or assembled with a high yield and high alignment robustness.
U.S. 60/200,002 disclose a so-called collimating trumpet reflector, which provides excellent color mixing for a LED light source and efficient collimation for inter alia hard edge spot fixtures as used in theatre spots. However, lighting designers may wish to use the same fixture to project an out of focus diaphragm to get a soft edge. Particularly in stage lighting, there is often a need to create a controlled beam of light having sharp edges. This is often realized using a so called hard edge spot luminary (also called a profile lantern or an ellipsoidal profile spot). The hard edge spot luminary may comprise obstructions arranged in the optical path or axis, which obstructions can be projected onto a target surface by a lens or optics of the hard edge spot luminary. These obstructions may comprise shutters or a so called gobo, e.g., a piece of material with patterned holes through which light passes, which piece of material is placed in the beam of light such that only the desired ‘shape’ of light or pattern is passed through the piece of material, while the rest of the light is blocked, thereby achieving a specific shadow/light pattern in the illuminated plane. Often in the same application, there is additionally often a need or desire to create a wash beam, i.e. a beam of light having soft edges. This is often realized by bringing the lens or optics of the hard edge spot luminary out of focus, whereby soft edge effects can be provided. However, color mixing performance often deteriorates when the lens or optics of the hard edge spot luminary is brought out of focus, which may result in undesired color fringes in the shadow/light pattern projected onto the target surface, i.e. undesired fringes of color along boundaries separating bright and darker areas in the projected pattern.